adrenelin5

To start I'm the recently proud owner (fingers crossed) of a 1994 LS 400.

Yesterday I tripped codes 43 and 51 on the trac indicator light.
No CEL or TRAC OFF indicator is coming up.


43 "malfunction in trac system" only it's found under "ABS codes" which I found confusing to start.
51 "problem with engine control system"

Spend most of day either working on car or researching with no luck.

I became tired of thinking about it and decided to retire for the night when it dawned on me.

I'm learning as I go but do have a theory.

43: indicates trac system malfunction, but code is listed under ABS section . So I figure ok perhaps its a brake issue.
51: indicates problem with engine control.
So ok . What does the engine have to do with controlling the brakes.

Vacuum?

Like I said I'm learning as I go. Technical stuff is beyond me. Mostly because I don't have many tools at my disposal to work with.

If this has been talked to death... my bad. I did honestly search and search and so on and so forth and then some to no avail.

Appreciate any insight. Thanks.

PureDrifter

iTrader: (10)

sounds like tps adjustment

adrenelin5

I see that the TPS is attached to the throttle body and that it can either be rotated one way or the other to low/heighten the idle speed. I assume this is the adjustment your referring to? If so my RPM gauge is way out to lunch and has always shown my RPMs at idle to be about 200 which I'm sure isn't the case because while I don't know if it's spot on the car doesn't shake.

adrenelin5

Does anyone else share this opinion?

To start with I won't be adjusting the factory manual way I'lll only be able to go the trial and error route. Since my RPM gauge is wacky this won't be easy. In my mind the only way is to mark it's position now and turn it one way then the other to see if the trac light stays off.

GS4_Fiend

iTrader: (22)

Code 43 - Conditions: ABS control system or TRAC (BRAKE) control system or communication circuit is abnormal
Causes: ABS & TRAC ECU. Open/Short in BRFA circuit.

Code 51 - Conditions: Fault seen at 500 RPM or more. Fault seen when Voltage of TRAC ECU terminal TR5 @ 1V or less.
Causes: Short in TR5 cirucit. Bad ECM. Bad TRAC ECU.

adrenelin5

Looking at the throttle body there looks to be 2 TPS ? one fairly close to the entrance and one at the air flows exit into the engine. From what I've found this is supposed to be on the non trac control cars. Is this a problem and if not do I just adjust the one near the air flow exit into the engine.

BTW I cleaned the TB yesterday and there were 2 butterfly valves. The first was all the way open.

adrenelin5

Both codes were tripped at the same time. So would that point to bad TRAC ECU?

adrenelin5

One more thought:

While trying to free up stuck inner/outer tie rods for alignment I noticed there was a fair amount of vertical lateral movement in the rotors/discs. I bought this car a month ago so I'm guessing the previous owner in an effort to save some cash tried to save a few bucks by using equipment made for a different vehicle.Over the last 3 days or so I've been noticing a strange noise from the area while braking which was about the same time the trac light came on.. Could this be it?

I'm going to go see if I can fabricate some spacers to insert around the studs this afternoon. In the mean time any thought would be appreciated.

PureDrifter

iTrader: (10)

unlikely that other rotors fit/worked.

more likely the pads are worn and the rotors are missing their hat screws.

cndnate

What about excessive bearing play in the wheel bearing/hub assembly? Have you checked for this?

On GM & buick cars the abs track sensor would go off as the bearing went - either the sensor was bring ground against soemthing or the resistance/sensor feedback was out of spec.

To test for bad wheel bearing:

1. jack car up so wheel is free,
2. check lateral/horizontal play by placing your hands at 9 and 3 (on a clock axis) and wiggle back and forth,
3. check vertical play by placing hands at 12 & 6 and wiggle back and forth.

adrenelin5

new pads no screw holes in dics

adrenelin5

I can say that there is play in that joint somewhere but I believe its either in the ball joint or steering damper if that makes sense. There is absolutly no noise that would be associated with a failing bearing.


I will look further into this.

For now the following seemed to take care of the trac light. Every time I drove until the drive after the following procedures the trac light would come on in less than half a mile. Post procedure I just drove about 40 miles without incident.

Because of a lack of hat screws or even a hole in the disc for them the rotor was easily moved in and out. I added spacers which I slid over the studs down into a space between the disc and stud pretty well eliminating any play. Perhaps incorrect rotors loosely vibrating around caused signal interference.

Secondly there was two wires that were joined together at the rear hub/caliper area but last week while changing pads the tape fell off.I cleaned it up and retaped it.

For now fingers crossed the light is absent. If any change I'll update.


Thanks for the help. Happy Easter.

adrenelin5

Last month noticed rear 02 sensor was sheared off, replaced and codes have not come up for a month of driving and I drive alot. Lexus has a funny (dumb) way of reporting 02 sensor malfunction. Hope this helps someone.

cndnate

Well I have a trac code 51 and and engine code #25. I guess I will check to see if my o2 sensors are connected!